It's a whole world of Perl out there. There's something called CPAN which is a
sort of "underneath the belly" thing for maintaining Perl modules. (Bugzilla is
based partly on Perl and such modules.) Installing Bugzilla, I had borked the
(required) installation/configuration of CPAN, I knew it, but I couldn't figure
out how to unbork it. I just did (mostly).

A big problem is that Perl/CPAN is (are) still stuck in the world of
ftp. I don't know anyone who uses ftp any more on Linux. We just no
longer really do that. I'm not yet certain fixing what I fixed here solves
that, but I was able to do some CPAN installs cleanly. This is a good link:

Do not run Perl and CPAN as root--ever. There is great risk (from what
I've read) of wiping your hard drive.

To run a CPAN shell, the source of all Perl module happenings, do

$ perl -MCPAN -e shell

If you've borked your CPAN stuff by choosing unwisely, zero it out by
launching (#2 above), then issing the shell command

cpan[1]> clean

Then, start over and take the defaults including the big one in letting the
thing make all the set up on its own. You will have to help it decide on a
list of mirrors at one point. Don't forget to commit changes:

cpan[2] o conf commit

After cleaning up and starting over, I was able to install YAML, the failure
of which prompted me to dig into this in the first place.

cpan[3]> install YAML

For one thing, as I was on Ubuntu server and hadn't installed them, I had to
get all the build tools (make et al.) since these are used by...

$ /usr/bin/perl install-module.pl --all

...to work the installation. Set this up using:

$ apt-get install build-essential

I still had some nasty things going on due probably to having tried to do this
stuff from root. I'll update this as soon as any make real problems that I have
to resolve.